Determining Propeller Erosion at the Stern of a Berthing Ship

This paper presents the findings from an experimental investigation in to the nature and extent of the scouring that occurs when a ship berths in front of a perpendicular quay wall within the confines of a harbor. It examines the interaction between the relative position of the quay wall to the central axis of the ship and the influence of angle of the vessel's rudder on the magnitude of the scouring produced. The experimental programme covered a range of sediment sizes, propeller diameters and speeds of rotation and rudder angles. Also, methods for calculating the depth of expected scour are presented in terms of initial semi-empirical equations for the data range under investigation.

Coxiella buvnetii infection of an aortic graft with multiple vertebral body erosion

Q fever is caused by Coxiella burnetii and often has an insidious clinical presentation. We describe a rare case of Q fever infection of an aortic graft presenting with pyrexia and constant severe midlumbar pain due to erosion of multiple vertebral bodies. After successful treatment with graft resection and extra-anatomic vascular reconstruction, the patient continues on lifelong antibiotic therapy. We also present regional Q fever epidemiologic data together with a review of all previously documented cases of Q fever infections of vascular prostheses.

Determining propeller induced erosion alongside quay walls in harbours using Artificial Neural Networks

In shallow waters, such as those found close to berth structures, the wash from a manoeuvring ship’s propeller can cause erosion of the seabed. This erosion can be increased if the wash intersects a berth structure. A number of researchers have undertaken model studies and used regression analysis to develop predictive relationships for the scouring action. This paper presents an experimental investigation with Artificial Neural Networks (ANN’s), used to analyse the results. The purpose of using ANN’s was to examine the prediction accuracy of the Networks in comparison with previous regression analysis methods. ANN’s were found to provide a more accurate method of predicting propeller wash scour than the equations presented by previous investigators.

Combination of CFD and DOE to analyse solid particle erosion in elbows

Solid particle erosion is a major concern in the engineering industry, particularly where transport of slurry flow is involved. Such flow regimes are characteristic of those in alumina refinement plants. The entrainment of particulate matter, for example sand, in the Bayer liquor can cause severe erosion in pipe fittings, especially in those which redirect the flow. The considerable costs involved in the maintenance and replacement of these eroded components led to an interest in research into erosion prediction by numerical methods at Rusal Aughinish alumina refinery, Limerick, Ireland, and the University of Limerick. The first stage of this study focused on the use of computational fluid dynamics (CFD) to simulate solid particle erosion in elbows. Subsequently an analysis of the factors that affect erosion of elbows was performed using design of experiments (DOE) techniques. Combining CFD with DOE harnesses the computational power of CFD in the most efficient manner for prediction of elbow erosion. An analysis of the factors that affect the erosion of elbows was undertaken with the intention of producing an erosion prediction model. © 2009 Taylor & Francis.